Renal Involvement in Antiphospholipid Syndrome

Primary antiphospholipid syndrome in a hemodialysis patient with recurrent thrombosis of arteriovenous fistulas

INTRODUCTION

The antiphospholipid syndrome is a systemic autoimmune disease defined by recurrent vascular and/or obstetrical morbidity that occurs in patients with persistent antiphospholipid antibodies.

CASE PRESENTATION

A patient on hemodialysis with a primary antiphospholipid syndrome presented with recurrent vascular access thrombosis, obstetrical complications, and positive lupus anticoagulant. The patient had multiple arteriovenous fistulas that failed due to thrombosis. The obstetrical morbidity was defined by one miscarriage at the 7th week of gestation and a pregnancy complicated by pre-eclampsia with preterm delivery at the 28th week of gestation. A thorough thrombophilia screening confirmed the presence of antiphospholipid antibody. Lupus anticoagulant was present in plasma, measured on two occasions 12 weeks apart.

CONCLUSION

Thrombophilias are inherited or acquired predispositions to vascular thrombosis and have been associated with thrombosis of the arteriovenous fistula. Patients on hemodialysis with recurrent vascular access thrombosis and presence of thrombophilia should be evaluated about the need for anticoagulant therapy with a vitamin K antagonist.

Zonal cortical scarring and tubular thyroidization in kidney biopsies of patients with SLE-histologic indicator for antiphospholipid antibodies

Antiphospholipid antibody syndrome (APS) is an acquired prothrombotic autoimmune disease caused by the presence of antibodies against anionic phospholipids or plasma proteins bound to phospholipids on cell membranes. It can be a primary disease or secondary to other autoimmune diseases, most commonly systemic lupus erythematosus (SLE). Laboratory testing for antiphospholipid antibodies (aPL) may be only transiently positive, so APS could be missed until a catastrophic thrombotic episode or pregnancy morbidity occurs. In the kidneys, this manifests as thrombotic microangiopathy (TMA), and patients present with hypertensive urgency and acute kidney injury. However, APS may not always have a catastrophic presentation but instead a more smoldering course. Kidney biopsy may not show obvious active TMA lesions but rather only chronic injury in the form of zonal cortical scarring and tubular thyroidization. Still, it may warrant anticoagulation therapy. So it is important to recognize this pattern of injury in the biopsy. Herein, we retrospectively study the correlation between presence of this histologic feature in kidney biopsies of SLE patients and positive aPL testing results (anticardiolipin antibodies and/or lupus anticoagulant). Kidney biopsies of SLE patients from 2004 to 2015 ( n = 186) were screened for presence or absence of zonal cortical scarring. Their electronic medical records were reviewed for aPL results. Our study showed low sensitivity (33%) but higher positive predictive value (62%), specificity (89%) and negative predictive value (71%). This histologic finding is therefore not a sensitive screening tool, but if present, greatly increases the likelihood of underlying aPL. We want to emphasize that recognition of this histologic feature in the biopsies of SLE patients is important so as not to miss the opportunity to treat with anticoagulation therapy and possibly slow down the chronic renal damage.

Lupus Nephritis with Coexistent Antiphospholipid Antibodies Associated Nephropathy: A Case Report and Literature Review

Antiphospholipid syndrome (APS) associated nephropathy is a distinct clinical entity and can occur in patients with systemic lupus erythematosus (SLE) independent of or associated with lupus nephritis. Associated APS nephropathy in a patient with lupus predicts poor renal outcome, especially if left untreated. Recognizing a coexistent APS nephropathy in a patient with lupus nephritis is of utmost importance. Here, we present a patient with severe lupus nephritis with antiphospholipid antibodies (aPLs) who had no thrombotic manifestations of APS clinically. On renal biopsy, she was found to have APS nephropathy. Remission was achieved after 3 months of anticoagulation and immunosuppression. This case illustrates the importance of renal biopsy in a patient of SLE with aPLs. Renal biopsy often alerts a treating rheumatologist of the presence of thrombotic involvement in such patients, thereby altering the treatment of such patients.

Arterial stenosis in antiphospholipid syndrome: Update on the unrevealed mechanisms of an endothelial disease

First described in 1983, antiphospholipid syndrome (APS) is an autoimmune condition characterized by the occurrence of recurrent arterial and/or venous thrombosis, and/or pregnancy morbidity, in the setting of persistent presence of antiphospholipid antibodies (aPL). While thrombosis is the most well-known pathogenic mechanism in this disorder, the relevance of some other mechanisms such as arterial stenosis is being increasingly recognized. Arterial stenosis has been first described in the renal arteries in patients with APS, however intracranial and coeliac arteries can also be involved with various and treatable clinical manifestations. The underlying pathophysiology of this stenotic arterial vasculopathy is not fully understood but some recent studies revealed new insights into the molecular mechanism behind this endothelial cell activation in APS. In this review, we discuss these newly discovered mechanisms and highlight the diagnostic and therapeutic modalities of the APS related arterial stenosis.

Renal Thrombotic Microangiopathy in Proliferative Lupus Nephritis: Risk Factors and Clinical Outcomes: A Case-Control Study

BACKGROUND

Renal thrombotic microangiopathy (TMA) may be associated with lupus nephritis. Its relationship to other disease factors and its specific effect on prognosis are not precisely known. Evidence regarding these aspects is controversial, and information focusing on kidney-limited TMA in systemic lupus erythematosus (SLE) patients is scarce.

OBJECTIVES

The aims of this study were to identify risk factors for renal TMA in patients with lupus nephritis and to determine its impact on clinical outcomes.

METHODS

A case-control study was performed. We studied 245 renal biopsies from SLE patients. We included patients with renal TMA, as well as control subjects adjusted for glomerulonephritis class, estimated glomerular filtration rate, activity and chronicity indices, and follow-up time. Serological and clinical features were measured at the time of the biopsy and during follow-up.

RESULTS

Twenty-three patients with renal TMA and 21 control subjects were included. There were no differences in Systemic Lupus Erythematosus Disease Activity Index score, end-stage renal disease, or mortality between groups during follow-up. After multivariate analysis, lymphopenia (odds ratio, 10.69; 95% CI, 1.35-84.74) and anti-Ro antibody positivity (odds ratio, 8.96; 95% CI, 1.49-53.57) remained significantly associated with renal TMA.

CONCLUSIONS

Lymphopenia and anti-Ro positivity are independent risk factors for renal TMA in SLE patients. This increased risk could be a consequence of the potential role of these factors in endothelial dysfunction and damage. Outcomes were similar for patients with the same estimated glomerular filtration rate and biopsy characteristics, regardless of the presence of TMA.

A importância de reconhecer a síndrome antifosfolípide na medicina vascular

A síndrome antifosfolipíde (SAF) é uma doença autoimune sistêmica caracterizada por trombose arterial ou venosa recorrente e/ou morbidade gestacional e pela presença dos anticorpos antifosfolipídeos, podendo apresentar outras manifestações vasculares, como microangiopatia, arteriopatia crônica e SAF catastrófica. Determinados testes laboratoriais para a síndrome (por exemplo, o anticoagulante lúpico) podem sofrer interferência do uso de medicações anticoagulantes, dificultando o diagnóstico. A fisiopatologia da SAF é complexa, sendo enumerados no texto diversos mecanismos patogênicos relacionados à coagulação, ao endotélio e às plaquetas. Por fim, discutimos o tratamento da SAF de acordo com a presença e o tipo de manifestações clínicas, o uso dos anticoagulantes orais diretos e o manejo perioperatório de pacientes com SAF.

Antiphospholipid Syndrome and Kidney Involvement: New Insights

Antiphospholipid syndrome is an autoimmune disorder characterized by vascular thromboses and pregnancy morbidity associated with antiphospholipid antibodies: lupus anticoagulant, IgG or IgM anticardiolipin or anti-beta 2-glycoprotein I. The kidney is one of the major target organs in antiphospholipid syndrome (APS). However, beyond the known involvement of the kidney in primary and associated APS, we may be observing a new form of APS within the context of renal failure. This review describes the classical kidney manifestations of APS and provides new considerations to be taken into account.

The antiphospholipid syndrome: from pathophysiology to treatment

Antiphospholipid antibody syndrome (APS) is an autoimmune acquired thrombophilia characterized by recurrent thrombosis and pregnancy morbidity in the presence of antiphospholipid antibodies (aPL). APS can be primary, if it occurs in the absence of any underlying disease, or secondary, if it is associated with another autoimmune disorder, most commonly systemic lupus erythematosus. The exact pathogenetic mechanism of APS is unknown, but different, not mutually exclusive, models have been proposed to explain how anti-PL autoantibodies might lead to thrombosis and pregnancy morbidity. Diagnosis of APS requires that a patient has both a clinical manifestation (arterial or venous thrombosis and/or pregnancy morbidity) and persistently positive aPL, but the clinical spectrum of the disease encompasses additional manifestations which may affect every organ and cannot be explained exclusively by a prothrombotic state. Treatment for aPL-positive patients is based on the patient's clinical status, presence of an underlying autoimmune disease, and history of thrombotic events. In case of aPL positivity without previous thrombotic events, the treatment is mainly focused on reduction of additional vascular risk factors, while treatment of patients with definite APS is based on long-term anticoagulation. Pregnancy complications are usually managed with low-dose aspirin in association with low molecular weight heparin. Refractory forms of APS could benefit from adding hydroxychloroquine and/or intravenous immunoglobulin to anticoagulation therapy. Promising novel treatments include anti-B cell monoclonal antibodies, new-generation anticoagulants, and complement cascade inhibitors. The objective of this review paper is to summarize the recent literature on APS from pathogenesis to current therapeutic options.

Catastrophic APS in the context of other thrombotic microangiopathies

The catastrophic antiphospholipid syndrome (CAPS) is a rare disease that affects 1 % of cases with antiphospholipid syndrome (APS). CAPS can mimic or overlap with different thrombotic diseases; many patients present with a microthrombotic storm or thrombotic microangiopathic hemolytic anemia (TMHA). Thus, the differential diagnosis of CAPS includes thrombotic thrombocytopenic purpura (TTP), typical and atypical hemolytic uremic syndrome (HUS), systemic infections, malignancies, pregnancy-related disorders, malignant hypertension, heparin-induced thrombocytopenia, and drug-induced thrombotic microangiopathies. Antiphospholipid antibody (aPL) positivity has been proposed as the clue in this differential diagnosis; however, aPL can also occur in healthy people and in those with infections or malignancies. Thus, the differential diagnosis of an aPL-positive patient presenting with a microthrombotic storm is broad; the workup should include a special attention to signs of infection and disseminated malignant disease, assessing the funduscopic signs of malignant hypertension, testing ADAMTS13 activity and anti-heparin-platelet factor 4 (HPF4) antibodies, and searching previous exposure to certain drugs. This article aims to review the main diseases included in the differential diagnosis of CAPS in the context of other thrombotic microangiopathies.

An approach to differential diagnosis of antiphospholipid antibody syndrome and related conditions

The antiphospholipid antibody syndrome is a systemic, acquired, immune-mediated disorder characterized by episodes of venous, arterial, or microcirculation thrombosis and/or pregnancy abnormalities, associated with the persistent presence of autoantibodies, confirmed at least in two occasions 12 weeks apart, directed to molecular complexes consisting of phospholipids and proteins. Antiphospholipid antibody syndrome should always be considered as a potential diagnosis especially for young patients presenting with a history of thrombotic events, in particular when they occur without any obvious external trigger or any inherited thrombophilic mutation (even if 2006 criteria do not exclude antiphospholipid antibody syndrome in patients with other inherited or acquired prothrombotic conditions), or for women with recurrent pregnancy losses or later fetal deaths. Many other disorders are able to mimic antiphospholipid antibody syndrome, so a broad range of alternative diagnoses should be investigated and ruled out during clinical workup.